<title>Image sensing with programmable offset pixels for increased dynamic range of more than 150 dB</title>

Abstract

A novel CMOS active pixel sensor structure has been designed, fabricated and characterized. It greatly increases the working range for all imaging applications in which the optical signal information to be detected is superimposed on a large DC offset signal. This is achieved by subtracting an offset current at each pixel's photosite. The offset current can be programmed individually by an external programming voltage. Experimental results from a single pixel test-cell fabricated on a standard 2 (mu) CMOS-process show a programmable offset signal range of > 150 dB with a dynamic range of > 60 dB of the photo detector itself. To achieve a similar performance using conventional imaging techniques would require an imager with a dynamic range of > 150 dB.